The invention is related to routing telephony communications directed to customers of an Internet Protocol (IP) telephony service provider. An IP telephony service provider is capable of offering telephony services to its customers that are highly similar to the services offered by traditional telephony service providers. For example, an IP telephony service provider can assign a telephone number to a customer and/or the customer's telephony devices. The IP telephony service provider can then connect an outgoing telephone call placed by the customer to another telephone number served by the IP telephony service provider, or by any other telephony service provider. The IP telephony service provider can also connect an incoming call directed to a customer's telephone number to one or more of the customer's telephony devices.
In the United States, groups or blocks of telephone numbers are assigned to individual local exchange carriers, and the local exchange carriers then assign individual telephone numbers to their customers. Because an IP telephony service provider is not a typical local exchange carrier, groups of telephone numbers are not directly assigned to IP telephony service providers. Instead, an IP telephony service provider must obtain control over a group of telephone numbers via a contractual agreement with a local exchange carrier to which the group of telephone numbers were originally assigned. The IP telephony service provider can then assign the telephone numbers to its customers.
At one point in time, a customer's telephone number was indicative of the identity of carrier that assigned and controlled the telephone number. As a result, when a first carrier was attempting to route an outgoing telephone call for one of its customers that was directed to a telephone number controlled by a second carrier, simply examining the telephone number to which the call was directed provided an indication of the identity of the second carrier. This made it easy for the first carrier to determine how to route the call.
In the recent past, however, legislation in the United States mandated that a customer be capable of retaining a telephone number assigned to them when the customer switches from a first telephony service provider to a second telephony service provider. One consequence of this change is that a customer's telephone number is now not necessarily indicative of the identity of the carrier that currently provides the customer with its telephony service.
For example, a customer could sign up for telephony service with a first telephony service provider, and the first telephony service provider would assign one of the telephone numbers it controls to the customer. Later, the customer could switch to a second telephony service provider, but retain the telephone number originally assigned by the first telephony service provider. When a third telephony service provider attempts to send a call to the customer, the third telephony service provider must be made aware that the first telephony service provider that originally controlled and assigned the telephone number is no longer capable of completing a call to that telephone number. Instead, the third telephony service provider needs to direct the call to the second telephony service provider.
To address this issue, local number portability databases were established. When control of a telephone number is switched from a first telephony service provider to a second telephony service provider, an entry for the telephone number is made in the local number portability databases. The entry includes a “location routing number” which is associated with that telephone number. The location routing number is a ten digit number that resembles a telephone number, but is not a telephone number. Instead, the location routing number provides an indication of the identity of the telephony service provider that currently provides service to the telephone number. More specifically, the location routing number can be indicative of the identity of a switch or gateway that services the telephone number and which is capable of terminating an incoming telephony communication to the telephone number.
Now, whenever a carrier needs to send a telephony communication to a called telephone number, the carrier first checks the local number portability database to determine if there is an entry for the called telephone number. If not, this means that the telephone number is still being serviced by the telephony service provider that originally assigned the telephone number. As a result, the telephone number itself will provide an indication of the identity of the telephony service provider capable of terminating the telephony communication to the called telephone number.
On the other hand, if there is an entry for the called telephone number in the local number portability database, this means that the telephone number is now being serviced by a telephony service provider other than the one which originally assigned the called telephone number. In this instance, the entry in the local number portability database for the called telephone number will include a location routing number. And the location routing number corresponding to the called telephone number will provide an indication of the identity of the telephony service provider capable of terminating the telephony communication to the called telephone number.
As mentioned above, when an IP telephony service provider wishes to assign a telephone number to one of its customers, the IP telephony service provider must first obtain control of a telephone number from a first local exchange carrier. If there is an entry in the local number portability databases for the telephone number, the entry will include a location routing number that identifies the first local exchange carrier.
When a calling party utilizing a second local exchange carrier dials the telephone number of the customer of the IP telephony service provider, the second local exchange carrier consults the local number portability database for the called number, and finds an entry which includes a location routing number identifying the first local exchange carrier. As a result, the second local exchange carrier sends the call to the first local exchange carrier. The first local exchange carrier determines that the call is for a customer of the IP telephony service provider, so the first local exchange carrier passes the call along to the IP telephony service provider. The IP telephony service provider then terminates the call to its own customer which has been assigned the called telephone number.
While this sequence of steps results in the call ultimately being connected to the called party, the process is inefficient. The call is routed from the second local exchange carrier to the first local exchange carrier, and then from the first local exchange carrier to the IP telephony service provider. The interim step of routing the call through the first local exchange carrier can delay the call setup. In addition, the IP telephony service provider may be forced to compensate the first local exchange carrier for re-routing the call. It would be desirable to have the call sent directly from the second local exchange carrier to the IP telephony service provider. Doing so would result in a faster call setup. A direct connection would also avoid burdening the first local exchange carrier with re-routing the call, freeing the assets of the first local exchange carrier for other tasks. Moreover, it is potentially less expensive if the assets of the first local exchange carrier are not used to route the call to the called party.